(196e) In-Situ Treatment of Pinewood Pyrolysis Vapors Using Zeolites

Pine wood pyrolysis vapors were treated in-situ using zeolite catalysts. An auger fed reactor was used for the pinewood pyrolysis, while a packed bed reactor mounted on the top of auger reactor housed the catalyst was used to treat the pyrolytic vapors. The pyrolytic vapors produced at 450 ^oC were passed through zeolite catalysts maintained at 450 ^oC at a weight hourly space velocity (WHSV) of 12 h^-1.  Seven zeolites, including three HZSM-5 catalysts with differing SiO₂/Al₂O₃ratio (23, 55, and 280), as well as mordenite, ferrierite, HY, and beta, were used as catalysts. The effect of catalyst type on deoxygenation of pyrolysis vapors was studied.  Chemical characterization of the upgraded bio-oils was performed using GC-MS. Water content, density, viscosity, acid value, pH, and elemental composition of each upgraded bio-oil was also measured. Catalyst characterization was performed using XRD, TEM, and TGA.

Catalytic treatment of pyrolysis vapors decreased the liquid yield at the expense of gaseous product. While all the zeolites deoxygenated the pyrolysis vapors, HZSM-5 catalysts were most effective. The HZSM-5 upgraded bio-oils were less viscous, had low acid number, high pH, and an oxygen content half that of untreated pyrolysis oil. HZSM-5 catalysts also produced the highest amount of phenolics and aromatic hydrocarbons. Acidity, pore size, and the shape selective catalysis of HZSM-5 catalysts were responsible for their high activity. TG analysis revealed that the pore size of the catalysts highly influenced the coking reactions. Catalysts were successfully regenerated.